Recent experimental and theoretical studies [1]}, [2]}, [3]} have shown that receptor clustering is also an important source of intracellular fluctuation. In other words, enhanced sensitivity comes at the cost of increased biochemical noise. This results in an optimum size of the receptor cluster, or equivalently, an optimum strength of the cooperative interaction between the receptors, for which the cell shows the most efficient chemotaxis. The origin of this optimality is distinctly different from the optimal signaling team size observed for a noisy input signal, when due to amplification of that noise the chemotactic performance gets adversely affected for very large signaling teams [4]}. We had shown in an earlier work [3]} that even in absence of any noise in the ligand environment, there exists an optimal size of the signaling team when the chemotactic performance is at its best. We had calculated different quantities characterizing the chemotactic performance and shown how each of them reaches a peak at a specific size of the signaling team [3]}.
